This is the only reliable before and after post with CRC I could find where someone actually did it with pics.
"So I got a chance to do the A, B test of the CRC GDI cleaner today in combination with an oil change.
A: Take manifold off, take before photos of valves (potatoes 1 & 2)
Install manifold, spray CRC GDI cleaner according to instructions
B: Take manifold off again, take after photos of valves (potatoes 3 & 4)
Unfortunately, photos came out terrible.
However, I will say that the simple spray on cleaners actually did take a substantial amount of the goop off- but not nearly close to what a proper walnut blast would do.
The mechanism seems to be heat and some kind of strong detergent. After application the intake manifold and associated parts of the engine bay were quite hot. It took over an hour to even partially cool and for me to stop burning my hands in the "after" tear down. I didn't happen to have any of my long Q-tips to swab the valves, but all the nasty stubborn oily deposits in the manifold and throttle body simply wiped away.
Mechanism for delivery: inserting the straw into the boost tube post intercooler, pre throttle body.
Car: stock as stock gets MS3 engine, including EGR no CC.
The verdict: if it's cheap and available, sure, throw a can the car for a regular maintenance. HOWEVER, not a replacement for a yearly walnut cleaning. Or an additional helper to cut down on soaking for walnut blasting."
http://www.mazdaspeedforums.org/forum/f1...399/index3.html
So maybe if you do it enough times, it will actually start making a difference, but the hard baked on deposits will only come off via manually scrubbing with the intake manifold off or walnut blasting.